Preparation of granular X-type zeolite/activated carbon composite from elutrilithe by adding pitch and solid SiO2

The preparation of granular X-type zeolite/activated carbon composites from a locally available elutrilithe by adding pitch powder and solid SiO₂ was studied, and the variations in the synthesis process of zeolite X were investigated. The preparation steps of the composite involved (1) calcination of pre-shaped mixture (2) activation of the carbonaceous material from elutrilithe and pitch to prepare activated carbon and (3) hydrothermal conversion (zeolitisation) of aluminosilicate in elutrilithe and additional SiO₂ to zeolite X in alkaline medium. The adding of additional SiO₂ in the reaction system to adjust SiO₂/Al₂O₃ ratio of the reaction mixture was necessary for the formation of zeolite X. The characterization of XRD, SEM and N₂ adsorption of the resulting composites had a hierarchical pore structure, which shows that pure X-type zeolite phase with high crystallinity could be obtained regardless of the content of carbon in the composites.     

Design,preparation, and application of ordered porous polymer materials

Ordered porous polymer (OPP) materials have extensively application prospects in the field of separation and purification, biomembrane, solid supports for sensors catalysts, scaffolds for tissue engineering, photonic band gap materials owing to ordered pore arrays, uniform and tunable pore size, high specific surface area, great adsorption capacity, and light weight. The present paper reviewed the preparation techniques of OPP materials like breath figures, hard template, and soft template. Finally, the applications of OPP materials in the field of separation, sensors, and biomedicine are introduced, respectively.     

Enhancing the efficiency of AuCl4 ion removal from aqueous solution using activated carbon and carbon nanomaterials

The removal of AuCl₄⁻ ion from acidic aqueous solutions is studied using a series of non-oxidized and surface oxidized carbon materials (activated carbon, carbon nanotubes, carbon-encapsulated iron nanoparticles and carbon black). The studied sorbents differ in crystallinity, porosity and morphology. In the case of non-oxidized carbon materials the maximum removal efficiency (74%) is found for activated carbon, whilst graphitized nanomaterials (i.e. carbon nanotubes and carbon-encapsulated iron nanoparticles) are able to remove 42–45% of gold ion from the solution. The oxidation in nitric acid significantly improves the removal efficiencies. The uptake of Au(III) increases two times (to 91–92%) for oxidized carbon nanotubes and carbon-encapsulated iron nanoparticles. The same oxidation procedure applied to activated carbon and carbon black moderately enhances the uptake efficiency to 88% and 55%, respectively. The observed substantially distinct uptakes are discussed in the frames of textural properties, morphology, surface chemistry characteristics and crystallinity of the studied carbon materials. Moreover, the possibility of a galvanic exchange reaction between AuCl₄⁻ and metallic Fe in the carbon encapsulate core is also evaluated.     

MgO-templated porous carbons-based CO2 adsorbents produced by KOH activation

Nanoporous (styrene–divinylbenzene)-based ion exchange resin-based carbons (MPCs) were prepared by MgO-templating synthesis and activated by KOH. MPCs were prepared from a (styrene–divinylbenzene)-based ion exchange resin by the carbonization of a mixture with Mg gluconate at 900 °C. And then, the prepared MPCs were treated with KOH at KOH/MPCs ratios ranging from 0.5 to 4 at 800 °C. Low KOH/MPCs ratios (KOH/MPCs ratio = 1) tended to favor the formation of micropores, whereas higher KOH/MPCs (KOH/MPCs ratio = 4) led to the formation of mesopores. The treated MPCs with a KOH/MPCs ratio = 1 exhibited the best CO₂ adsorption value of 266 mg g⁻¹ at 1 bar. However, the treated MPCs with a KOH/MPCs ratio = 3 exhibited the best CO₂ adsorption value of 1385 mg g⁻¹ at 30 bar. This result indicated that the CO₂ adsorption capacity of nanoporous carbons attributed to the mesopore volume fraction at higher pressure.     

One-pot synthetic method to prepare highly N-doped nanoporous carbons for CO2 adsorption

A one-pot synthetic method was used for the preparation of nanoporous carbon containing nitrogen from polypyrrole (PPY) using NaOH as the activated agent. The activation process was carried out under set conditions (NaOH/PPY = 2 and NaOH/PPY = 4) at different temperatures in 600–900 °C for 2 h. The effect of the activation conditions on the pore structure, surface functional groups and CO₂ adsorption capacities of the prepared N-doped activated carbons was examined. The carbon was analyzed by X-ray photoelectron spectroscopy (XPS), N2/77 K full isotherms, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The CO₂ adsorption capacity of the N-doped activated carbon was measured at 298 K and 1 bar. By dissolving the activation agents, the N-doped activated carbon exhibited high specific surface areas (755–2169 m² g⁻¹) and high pore volumes (0.394–1.591 cm³ g⁻¹). In addition, the N-doped activated carbons contained a high N content at lower activation temperatures (7.05 wt.%). The N-doped activated carbons showed a very high CO₂ adsorption capacity of 177 mg g⁻¹ at 298 K and 1 bar. The CO₂ adsorption capacity was found to be dependent on the microporosity and N contents.     

Magnetic properties and methylene blue adsorptive performance of CoFe2O4/activated carbon nanocomposites

Owing to the unique microporous structure and high specific surface area, activated carbon (AC) could act as a good carrier for functional materials. In this paper, CoFe₂O₄/AC nanocomposites were prepared by a facile hydrothermal method for the adsorption of dyes in wastewater. The results indicated that CoFe₂O₄ nanoparticles presented the spinel structure and existed in the pores of AC. The saturation magnetization (Ms) increased with the CoFe₂O₄ content, while the surface area and pore volume decreased. For the larger magnetic moment, very few CoFe₂O₄ were needed to maintain the higher surface area of CoFe₂O₄/AC nanocomposites. The sample-5 (CoFe₂O₄:C = 1:200) possessed the surface area of 1096.85 m² g⁻¹ (close to 1243.35 m² g⁻¹ of AC) and Ms of 5.11 emu g⁻¹, which were sufficient for magnetic separation in wastewater treatment. 99% methylene blue could be adsorbed in 50 min, and then the CoFe₂O₄/AC nanocomposites could be separated from the solution easily by an outer magnet.     

High rate capability of Cu-coated activated carbon electrodes for Li-ion capacitors using non-aqueous electrolytes

A novel type surface modified activated carbon (AC) was prepared using the electroless deposition method as a new attempt to modify AC for Li-ion capacitors. The resulting Cu-coated AC exhibited higher specific capacitance than that of AC under a high cycling rate of 100 C. This result suggests that Cu nanoparticles play an important role in enhancing the rate capability of AC. The improved cell performance might be attributed to the reduced charge transfer resistance between the Cu-coated AC electrode and organic electrolyte while maintaining surface stability.     

Effect of preparation conditions on the hydrogen storage capacity of activated carbon adsorbents with super-high specific surface areas

A series of activated carbon adsorbents with super-high specific surface areas (SHAC) (S_BET ≥ 2500 m² g⁻¹) was prepared and used to adsorb storage hydrogen. The results indicated that the structure of activated carbon adsorbents and hydrogen storage capacity are affected by preparation conditions. The influence of preparation conditions on hydrogen storage capacity can be attributed to changes in the structure of the prepared activated carbon adsorbents. The prepared adsorbents had high hydrogen storage capacity, reaching 5.65 wt % and 4.98 wt % when the adsorption temperatures were 0 °C and 25 °C, respectively, and the pressure was 9.0 MPa.     

Water vapor adsorption of CaCl2-impregnated activated carbon

Activated carbons (AC) impregnated with the hygroscopic salt CaCl₂ were synthesized to enhance the amount of water vapor adsorbed at low relative pressure (P/P₀). Possible applications for these materials are in adsorption heat pumps and desiccant air conditioners. The ACs were synthesized from tissue paper by chemical activation with K₂CO₃ and the porous properties were investigated of a number of materials prepared under a variety of activation conditions. The highest specific surface area (S_BET) (1820 m²/g) was obtained from the sample prepared with a K₂CO₃/sample ratio = 1/1 by mass, activated at 900 °C for 2 h under flowing N₂ (2 L/min). Impregnation with CaCl₂ was performed using 2.4-6.5 M CaCl₂ solutions and a solution volume equal to the pore volume of the AC. XPS surface chemical analysis revealed that the impregnated CaCl₂ was mostly successfully impregnated into the pores while the surface CaCl₂ increased gradually with increasing amount of impregnation. The adsorption of water vapor in the P/P₀ range 0.1-0.3 (ΔW_0.1-0.3) was dramatically increased by CaCl₂ impregnation, the ΔW_0.1-0.3 value reaching 0.52 g/g in the sample impregnated with 70 mass% CaCl₂; this value is much higher than previously reported ΔW_0.1-0.3 values.     

Porosity of resorcinol-formaldehyde organic and carbon aerogels exchanged and dried with supercritical organic solvents

Organic and carbon aerogels have been prepared from resorcinol-formaldehyde resin diluted with various amounts of water. Water was exchanged by acetone or ethanol, and the gels were subsequently dried with supercritical acetone or with supercritical ethanol. We showed that the nature of the solvent with which water was exchanged only had a minor impact on the porosity of the resultant aerogels. In contrast, the same solvents used as drying fluids in the supercritical state led to significant differences, but only in the case of diluted gels. When the initial dilution was low, similar results were indeed obtained with both solvents. Ethanol was shown to lead to higher shrinkages and higher bulk densities than acetone. A higher chemical degradation of the resin during the drying process was also observed when ethanol was used.     

Superior prospect of chemically activated electrospun carbon fibers for hydrogen storage

In this study, the capacity of hydrogen storage was evaluated by using electrospun activated carbon fibers prepared by electrospinning and chemical activation based on the comparison with other carbon materials such as active carbon, single walled carbon nanotube, and graphite. For an improved hydrogen storage system, the optimized conditions of carbon materials were investigated with studying their specific surface area, pore volume, size, and shape. The hydrogen adsorption capacity of chemically activated electrospun carbon fiber itself is better than that of other porous carbon materials. This is attributed to the optimized pore structure of electrospun activated carbon fibers that might provide better sites for hydrogen adsorption than other carbon materials.     

高温热处理对活性炭纤维微孔及表面性能的影响

研究了1173K高温改性处理对沥青基活性炭纤维吸附性能、孔径分布、微孔结构和表面化学的影响。低温(77K)N2吸附结果表明热处理后活性炭纤维比表面积略有下降，通过密度函数理论解析活性炭纤维全孔范围的孔分布得出活性炭纤维表面孔径大于1．0nm的微孔明显减少，微孔孔径更加集中于0．5nm～1．0nm，从而提高了活性炭纤维的碘吸附值。X射线衍射分析表明活性炭纤维是乱层石墨结构，热处理使活性炭纤维类石墨微晶碳层面的层间距下降，X光电子能谱分析表明热处理后活性炭纤维表面的含氧官能团C=O和COOH的含量变化不大，而呈碱性酚羟基C—OH含量的明显下降使活性炭纤维表面碱性降低。     

石油焦系超级活性炭的孔结构控制

采用KOH活化法从大庆石油焦制得超级活性炭，而后对其进行微孔和中孔的调控。中孔调控采用热处理法，所得超级活性炭的中孔率在85％以上，比表面积大于1500m^2／g。同时对热处理后的超级活性炭进行表面硝酸氧化，引入部分含氧官能团。60min酸处理效果明显，羧基的增加量是20min酸处理的9倍。处理后的超级活性炭更适合作催化剂载体。微孔的控制采用化学气相炭沉积法（以苯为碳源），所得超级活性炭的微孔率从51％增加到87％。对CO2和CH4的分离能力从30mg／g提升到47mg／g，具有良好的筛分效果。     

Activated carbon nanofibers derived from coconut shell charcoal for dye removal application

Activated carbon nanofibers (ACNF) have been successfully prepared using an electrospinning method with coconut shell charcoal (CSC) as a carbon source and poly(vinyl alcohol) (PVA) as a spinning polymer agent. The high voltage of 10 kV was applied for the electrospinning system. The positive electrode of the high voltage power supply was connected to the needle tip, and the grounded electrode was connected to the metallic collector wrapped with an aluminum foil. The dry fibers in the form of a fibrous mat were collected in the aluminum foil. The average pore diameters of the generated fibers for all variables ranging from 2.23 to 3.73 nm corresponding to mesoporous carbon nanofibers. The total pore volumes were ranging from 0.50 to 0.92 cm³/g. IACNF-60 had the largest surface area of 1,277 m²/g obtained from the use of PVA 12 w/v %, 60 wt% CSC, and the use of iodine treatment before thermal stabilization, carbonization, and activation stages. Methylene blue solution was used as a model for the dye adsorption capacity that followed the Langmuir adsorption model. IACNF-60 also indicated the highest theoretical maximum monolayer adsorption capacity in the amount of 166.7 mg/g. Furthermore, the methylene blue removal ability of IACNF-60 for the third cycle was maintained relatively constant at 96%.     

Preparation and properties of poly(urea–formaldehyde) microcapsules filled with epoxy resins

The poly(urea–formaldehyde) (PUF) microcapsules filled with epoxy resins have potential for self-healing or toughening polymeric composites. A series of PUF microcapsules containing epoxy resins were synthesized by selecting different process parameters including surfactant type, surfactant concentration, adjusting time for pH value and heating rate. The effects of process parameters on the size and surface morphology of microcapsules were discussed. The storage stability, solvent resistance and the mechanical strength of microcapsules were investigated. The morphology of microcapsules was observed using scanning electron microscopy (SEM) and optical microscopy (OM). The results indicate that the formation of microcapsules is affected by the surfactant type. The size of microcapsules can be controlled by the surfactant concentration. The surface morphology of microcapsules can be adjusted by the surfactant concentration, the adjusting time for pH and the heating rate. The microcapsules prepared by using surfactant sodium dodecylbenzene sulfonate (SDBS) show good storage stability, excellent solvent resistance and appropriate mechanical strength.     

基于纤维素纤维的多孔碳材料的制备及应用

采用选择性表面溶解（SSD）法将纤维素纤维表面部分溶解,固化后形成多孔结构,最后在Ar气氛中炭化制得多孔碳（HPC-SSD）材料,HPC-SSD材料具有大的比表面积和三维多孔结构。通过SEM、BET、FTIR、XRD及电化学测试,系统地研究了针对纤维素纤维的两种活化预处理方法对HPC-SSD材料的形貌、化学组成、比表面积及电化学性能的影响。通过与纤维素纤维直接炭化所得的多孔碳（HPC）材料的相关性能进行比较发现,HPC-SSD材料的成孔过程更加稳定,有利于大量微孔的形成。采用去离子水→丙酮→二甲基乙酰胺对纤维素纤维进行活化预处理,制得的HPC-SSD材料比电容为226 F·g-1（两电极体系）,是HPC材料的4.5倍,比未经过活化预处理的HPC-SSD材料提高了40%。      

Nitrogen-doped hierarchical porous carbon materials derived from diethylenetriaminepentaacetic acid (DTPA) for supercapacitors

Nitrogen-doped porous carbon materials (NPCs) have been successfully fabricated by a simple one-step pyrolysis of diethylenetriaminepentaacetic acid (DTPA) in the presence of KOH. The as-synthesized NPCs displayed a high specific surface area (3214?m²?g^?1) and a well-defined porous structure when the annealing temperature reached 800?°C, which showed superior electrochemical performance as supercapacitor electrode materials. Electrochemical tests showed that the NPCs achieved an impressive specific capacitance of 323?F?g^?1 at a current density of 0.5?A?g^?1 in 6?M KOH aqueous solution and an outstanding cycle stability, negligible specific capacitance decay after 5000 cycles at 10?A?g^?1. This strategy offered a new insight into the preparation of novel carbon materials for the advanced energy storage devices, such as supercapacitors, fuel cells and lithium ion batteries.     

柑橘皮中孔活性炭的制备及性能表征

以柑橘皮为原料,以氯化锌为活化剂,采用一步炭化法制备了中孔活性炭.研究了浸渍比、炭化温度及保温时间对孔结构的影响,通过BET、D-R方程、BJH方程及Kelvin理论表征了活性炭的孔结构,采用红外光谱分析样品的表面官能团,透射电镜观察微观形貌.柑橘皮中孔活性炭的适宜制备条件为:活化剂漫渍比3:1,炭化温度550℃,保温时间1h;所得活性炭中孔容积1.438cm3/g,中孔率占68.5%,BET比表面积为1476m2/g;该活性炭孔径分布集中,平均孔径3.88nm.利用中孔活性炭吸附垃圾渗滤液生化尾水,UV254值和TOC去除率分别为94.7%、66.4%.3DEEM证明该活性炭对DOM中的类富里酸具有良好的吸附性能,紫外区类和可见区类富里酸荧光强度分别降低49.1%、81.6%.     

基于低聚酰亚胺含氮介孔碳材料的制备

以低聚酰亚胺为氮源前驱体、交联酚醛树脂为碳源、嵌段共聚物为软模板剂,通过相分离自组装、交联和高温锻烧处理制备了新型高规整含氮介孔碳材料,并用FT-IR、SEM、TEM、热重分析和小角X光散射等测试方法表征介孔碳材料的组成与结构.结果表明,处理温度达350℃时嵌段共聚物模板可被成功移除,进而形成多孔结构;温度达600℃时体系完全碳化,可得到高规整的多孔含氮碳材料.通过调节体系中氮源、碳源及模板剂的相对比例可实现形貌由立方结构向柱状和层状结构的过渡,进而实现对含氮介孔材料形貌的有效调控.